Acid Test On Stone:
Acid test  conduct to determined how much atmospheric pressure can be resist by stone.

• A sample of Stone weighing about 50 to 100 gm. is taken. 
• It is placed in a solution of Sulfuric Acid or HCl having strength of 1% and is kept there for seven days. Solution is agitated at intervals.

• A good building stone maintains its sharp, size and  edges.
• They keep its surface free from powder at the end of this period.

If the stones having high percentage of lime content the following exhibit efflorescence has come.

• The edges are broken and powder is formed on the surface, it indicates the presence of calcium carbonate and other impurities  such a stone will have poor weathering quality.This test is usually carried out on sandstone.